The present invention relates to a sizing means and method for diametrically expanding a flexible tubular food casing just prior to the stuffing thereof. In particular, the present invention relates to an expandable sizing means together with a method for using the sizing means.
Automatic and semiautomatic techniques for stuffing food casings with a variety of food products are well known in the meat packing industry.
For production of encased products on a fully automatic basis, shirred casing is used. Shirred casing is simply a relatively long continuous length of casing of up to 200 feet or more which is shirred to a much shorter length. Other stuffing operations may use shorter, cut lengths of casing which are not shirred.
It is also common to use a casing sizing means in connection with the stuffing of larger casings which, for example may range between 50 to 200 millimeters in diameter. These casings have a relatively thick wall, often reinforced with a fibrous web. The stuffing of these reinforced casings is often facilitated by diametrically stretching the casing just prior to stuffing.
Casing sizing means as used to diametrically stretch the casing perform several important functions in connection with the stuffing operation. For example, stretching the casing to a correct diametrical size during the stuffing operation facilitates production of a stuffed casing product having a relatively uniform diameter throughout its length. This diametrical stretching can be accomplished simply by passing the casing over the sizing means and allowing the sizing means to stretch the casing to a predetermined diameter. This stretched casing diameter will be related to the manufacturer's recommended stuffed diameter for a given casing and is, or is near to, the final diameter of the stuffed product.
The friction between the casing and sizing means also creates an amount of drag or hold-back force on the casing. While this drag or hold-back, in part, contributes to the final diameter of the stuffed casing product, hold-back also determines the extent to which the casing is filled. In general, the greater the hold-back or drag on the casing, the more fully and tightly packed the casing with food product.
Regardless of the particular purpose for which the casing sizing means is used, there are times during the stuffing operation when the casing should be relatively free of the drag or hold-back force created by the sizing means. For example, during automatic stuffing operations of the larger sizes of casing, it is periodically necessary to provide an amount of casing slack, as when the stuffing apparatus is operated to gather and close the casing around the ends of the stuffed product. Reducing the drag or hold-back force on the casing in order to produce an amount of casing slack facilitates the gathering and closing operation.
Sizing means as used in stuffing of larger sizes of casing can have either a fixed diameter as shown for example in U.S. Pat. Nos. 4,007,761 and 4,335,488 or an adjustable diameter as shown in U.S. Pat. Nos. 3,457,588 and 4,202,075. The latter type, in turn, can comprise elements which are integral components of the stuffing apparatus (U.S. Pat. No. 3,457,588) or they can be attachable to the stuffing apparatus (U.S. Pat. No. 4,202,075).
The present invention is an expandable sizing means of the type which is readily attachable to the stuffing apparatus. Moreover, the sizing means is expanded to a casing stretching size by the action of the casing passing over the sizing means, so that no components are needed to force the sizing means to expand to a casing stretching size. This facilitates use of the sizing means, in that it can be easily implanted into a casing in a collapsed or unexpanded state, and then later expanded to a casing stretching size during the stuffing operation.
Thus, the sizing means of the present invention lends itself to sale either as a component of a casing article (casing plus sizing means) or as a separate item. For example, when sold as a component of a casing article, preferably together with a shirred casing length, the sizing means is simply implanted into an unshirred portion of the casing and the casing is closed over the sizing means. Since, in its collapsed state, the diameter of the sizing means is preferably smaller than the diameter of the unshirred, unstretched casing, the sizing means can be easily inserted into the unshirred casing portion.
In use, the sizing means is expanded to a casing stretching size only after the casing article is mounted to the stuffing apparatus and the stuffing operation is initiated.
When sold as a separate item, the sizing means can be used with either shirred or cut lengths of casing. When used with shirred casing, the sizing means is easily inserted into the casing and then mounted to the stuffing apparatus, or the casing can be loaded onto the apparatus followed by the sizing means. In any event, the shirred casing would be first on the stuffing apparatus since even in a fully collapsed state, the sizing means would probably not fit within the bore of a shirred casing stick.
When used with cut lengths of casing the order of mounting to the stuffing apparatus would not be critical, since the cut length would easily fit over the sizing means in its unexpanded condition.
During the stuffing operation, the sizing means is easily made to at least partly collapse so as to free casing for the gathering and closing of the casing over the ends of the product.